Morphometric analysis of lumbar pedicles among adult Kenyans using computer tomography scans and dry bone specimens

Abstract

Background: The use of pedicle screws in the lumbar spine is guided by the dimension and orientation of the lumbar pedicle.
Objectives: To determine the width, angulation and chord length of the lumbar vertebrae pedicle from L1 to L5 in adult Kenyans using Computer tomography scans and dry bone specimens.
Methods: Three hundred and thirty dry bones, 100 samples were selected systematically, and 100 CT scans from 468 lumbar spine scans. Results from the analysis were summarized as means, standard deviations and presented in line and bar graphs.
Results: Pedicle width mean measurements were L1-8.6mm, L2-9.6mm, L3-11.4mm, L4-13.5mm, L5-16.3mm on dry bone specimens. On CT scan pedicle width mean measurements were L1-7.2mm, L2-7.6mm, L3-9.2mm, L4-10.8mm, L5-14. 6mm. The mean angle of insertion on CT scan was L1-19.7o, L2-20.5o, L3-22o, L4-24.1o, L5-29.8o. Pedicle chord length measurements obtained were  L1-47.9mm, L2-48.9mm, L3-48.9mm, L4-47.7mm, and L5-47.0 mm on dry bone specimen. On CT scan it was, L1- 48.6mm, L2-49.9mm, L3-50.1mm, L4-49.8mm, and L5-50.1 mm.
Conclusion: The pedicle width on CT scan measurements increased from 7.2mm to 14.6mm and on dry bone specimen it increased from 8.6mm to 16.3mm between L1 to L5. The angulation increased from L1 to L5 on CT scan measurements from 19.7o at L1 to 29.8o at L5. The chord length range measurement on dry bone specimen ranged from 47.9mm to 48.9mm and on CT scan from 48.6mm to 50.1mm.